Enhancement of the performance of flexible lead-free nanogenerators by doping in BaTiO3 nanoparticles

Abstract

Barium Titanate (BaTiO3) lead-free ceramic has recently gained attention for the fabrication of nanogenerators. Herein, lead-free piezoceramics (Ba, Ca) (Zr, Ti)O3 was synthesized using the sol-gel method. In order to improve the material properties, Ca2+ and Zr4+ were introduced into the BaTiO3 crystal network to replace Ba2+ and Ti4+, respectively. Subsequently, three flexible nanocomposites were chemically fabricated by mixing polyvinylidene fluoride‐co‐hexafluoropropylene (PVDF-HFP) with the commercial BT, the synthesized BZT and BCZT, using the solution‐casting technique. The microstructure and morphology were characterized by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), and (SEM). This study illustrates that the combination of both addition Ca2+ and Zr4+ in barium titanate is promising for forming the electroactive β-phase in the nanocomposite. The XRD and FTIR confirmed the formation of the polar β-phase, enhancing piezoelectric properties. The electrical conductivity of the nanocomposite increased with doping in both sites. A maximum output voltage (∼1.8 V) and power (∼1.9 μW) were achieved for composite including BCZT particles. Besides, different sizes and concentrations of BCZT/PVDF-HFP based nanogenerators were constructed. The optimal performance was with nanogenerators of size 2 cm × 2.5 cm and 10 wt % of BCZT powders. Biomechanical foot-tapping achieved a maximum output voltage of 4.55 V, which was high enough to become a potential candidate for a self powered device in future applications.